Beware Of What You Stretch

Tue Mar 7, 2017 by Jason Glass


Do you know what will happen if you stretch that thing? Well then leave it alone! So many of us have bought into the old adage that you need to stretch to stay supple and play your best. What if stretching actually had the opposite effect? We think that the sensation of tightness requires the act of stretching and that improving range of motion increases performance.  

"If you're using 'flexibility' as an umbrella term for tightness, you're like a map maker who still insists the world is flat. Calling all limited range of motion problems flexibility issues is problematic because it suggests that all can be helped with stretching."

Gray Cook

Sometimes stretching is needed, sometimes stretching creates a performance change and sometimes stretching may actually make you worse. Wow! The secret is knowing what needs to be stretched, how to stretch it, how stretching will affect the rest of the body and, most importantly, when NOT to stretch! 


I loved the TV series Westworld. If you haven’t seen it you need to learn how to illegally download TV shows and movies and watch it. The idea is that there is a world made up of lifelike robots that humans pay money to explore their deepest desires. The opening credits show the process of strands of silicon being fabricated to imitate muscle fibres, tendons and ligaments. It is an amazing visual that makes you think about the engineering that makes up our complex bodies. 



If you tried to build one of these robots in your garage you would need some ropes, straps and bungee cords with a variety of different elasticity, stiffness and playability. This would be one serious undertaking that would require ingenuity and an phd in engineering and human anatomy. Lets make this a little more elementary and take the task of building the leg for instance. You would need to attach the bungee cords to the femur and run them across the front of the knee and attach them to the tibia. Then you would need to add some bands or cords to the backside of the leg to counteract the pull from the bands on the front.


Finding the right length, balancing out the strength of the elastic components and figuring out exactly how much range of motion you want that joint to have would quickly become your focus. What if one band is too long or can’t handle the forces that are applied to the opposite side of the joint? You will either have a poor performing joint or potentially snap something!


Managing the tension and length of tissues in the body parallels what physiotherapists, chiropractors and other soft tissue specialist deal with on a daily basis. Release the hip flexor and it affects glute activation. Change the length of the hamstring and you can change the athlete’s posture and pelvic position. Sometimes for the good and often bad things can come from aimlessly playing stretch it and see what happens.


I struggle with low back pain, bouts of sciatica, tight hip flexors, and tight hamstrings. This issue places my pelvis in an anterior tilt position. Much like the pelvic position of the world’s fastest men and women. Is my back problem a symptom of this tilted pelvis or is the tilted pelvis and tautness around the hips my body’s solution to help protect my low back from excessive flexion which aggravates the sciatic nerve? If we get some soft tissue work performed on my hip flexors I instantly feel taller, my posture changes all the way up the chain. My glutes can fire and my hamstrings feel loose. Shortly following this moment of bliss, low back starts to fatigue, pain shoots down my leg and I find myself being pulled back into the anterior tilted pelvis position again. One nights sleep and I am back to my old tilted self.


In the performance coaching world I work hand in hand with my medical team. The medical team will put the joint into an optimal position and I will strengthen the muscles around the joint to maintain that position. We like to call it “Reset & Reinforce”. The medical team resets the position of function of the joint or movement pattern and I reinforce that new range of motion or new pattern with exercises to reinforce it and make sure it stays.


So you may ask “Why can’t you do that for yourself?” A better question is if I am pain free with a tilted pelvis and can function and perform at a high level as a 44 year old strength coach, why change it?  Especially if changing it causes a cascade of pain and disfunction. Be careful what you stretch! Some say you need to reset and go through the pain while reinforcing it to get you through the other side pain free and functional. Is that a priority for a guy my age? Would I take a 20 year old world class athlete through that process and take them out of competition for months while we see if the fix sticks?


Segue…..I know there are a lot of you out there that either use the Functional Movement Screen (FMS) or have been through a FMS screen at some point in your career. There are parameters that are set and defined as functional norms. Lets take the Active Straight Leg Raise as an example. Lying on your back you raise a straight leg as high as you can. Medical norms would indicate that any ROM less than 80 degrees from the floor would be less than ideal. You then have the athlete relax and the screener can passively take the  leg through the same flexion pattern to see if the lack of ROM is a strength, core stability issue or a mobility issue. If it truly is a mobility issue you could use a plethora of soft tissue techniques to release the hamstring and lengthen it.



What if I told you that some of those fast sprinters that I discussed earlier with the anteriorly tilted pelvis will often fail the Leg Raise Test? Chalk it up as a coincidence or could having taut hamstrings in combination with tight hip flexors be the secret to speed? Altering the length of their hamstring may just take them from being in the top 1% of world class sprinters to not getting out of the blocks in the qualifying heats. 


The point of this blog post is to open your eyes to something we all take for granted. Stretching. In Episode 173 of the Coach Glass Podcast “Beware of What you Stretch” I share stories about exactly what is wrong with our industry that seems unable to provide training sessions without a happy stretching finish. When I started as a trainer 20 years ago I use to take each client through the exact same stretching process after their session. Regardless of their need. Some clients had over 90 degrees of  active straight leg raise but I still laid them down for their daily hammy stretch. “I don’t feel it Jay?” Well you are getting it either way because this what I have been told will help you feel better and perform at your best so relax and enjoy. Maybe some of you are in the same boat as I was 20 years ago. You are in a rut and just stretch people because thats just what you do. Hopefully after reading this post you will think about what you are stretching and whether or not you truly should be stretching it. Beware of what you stretch.


Jason Glass

Jason Glass BHK, CSCS, TPI Advisory Board @jasonglasslab Host of the Coach Glass Podcast on iTunes Website:

  • Pam Owens

    Great topic that challenges the simple approach of stretching or foam rolling everything that feels tight. Reset and reinforce can be accomplished in a variety of ways. I use a few tools to accomplish it too. Thanks again Jason.

  • OregonExercise

    Jason brings up some great points in this article. Some examples to maybe help explain: If you compare your typical 100m sprinter to your typical ballet dancer you will see very different ranges of motion of joints. Let's take the hips: sprinter much less hip flexion, extension, abduction, and rotation than the ballet dancer. The sprinter we could say has higher stability around their hips and the ballet dancer has higher mobility around their hips. Is stability or mobility better? It depends on your goals. So what would happen if you work to improve the sprinters range of motion until they have the same range of motion as the ballet dancer? They would not be nearly as fast! Why? To have explosive speed you need some tension from muscles and tendons. What would happen if you work to increase the ballet dancers stability? They would not be as good of a ballet dancer because they would lose range of motion needed to perform. But does this mean the sprinter should never work on mobility or the ballet dancer should never work on stability? No and no. The goal for both should be balance and function. Balance meaning left to right first of all in their body - our bodies need symmetry to perform any activity well and stay injury free. (examples of losing this balance can be seen in one shoulder or hip being higher than the other, one foot turning out more that the other, etc) Balance front to back is second - our bodies need balance between the muscles in the front and back of the body to perform well. (examples of losing this balance can be seen in anterior or posterior pelvic tilt, excessive lordosis or kyphosis, or forward head etc) The third type of balance we need is rotary balance (transverse view) - our bodies need balance of internal and external rotators to perform well. (examples of losing this balance is external or internal femur rotation, internally rotated arms, etc) The goal for any athlete (or person) is to maintain balance and then optimize their range of motion, stability, and function to perform their chosen activity optimally. A sprinter can have not enough range of motion which can decrease performance just as they can have too much range of motion which can also decrease performance. The goal is balance between range of motion and stability. Each athletes (or person's) strength and flexibility program should be personalized by a well qualified professional that knows the intricate balancing act of strength, flexibility, and function that each athlete needs for each sport/activity and can identify where each individual is out of balance and how they can improve.

  • Jason Glass

    Thanks to everyone who read this article and commented. Stretching is great for 90% of people 90% of the time. The point of this article is to bring awareness to a part of our fitness culture that we all just assume is right for everyone. Just be aware. It's not about do or don't but be aware!

  • Douglas Pudsey

    Jason, As a senior golfer in my 80ts stretching in the offseason is essential to my body. A quick two minute daily stretching of me hips and back by using deep knee bends and touching toes (cheating by allowing the legs to ease up a little bit to touch my toes) seems to work for me. My flexibility has never been a problem so far. I agree with you that some streches are not beneficial and in some cases can create the opposite effect and make things worse. Thank you for this article....cheers :-)

  • Margo Fonda

    A few years ago, I personally stretched too much. I agree, not all stretching is beneficial. Can you say high hamstring pull? In all things, moderation.

  • Jenya

    Jason, we, the mortals don't work with athletes, but with regular people. So my question to you is this - how many people, especially with Lower Cross Syndrome, do you think with not benefit from hip flexors and hamstrings stretched?

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